1. Field of the Invention
This invention relates generally to a hydrocarbon conversion catalyst and method and more particularly concerns a catalyst and method for recovering upgraded liquid products from coal, coke, lignite, petroleum fractions, biomass, tar sands bitumen and shale oil.
2. Description of the Prior Art
It is generally desirable to provide a catalyst having a high level of small- or intermediate-sized pores because, for a given total pore volume, distribution thereof in many smaller pores gives a relatively higher surface area than distribution thereof in a smaller number of relatively larger pores. However, small pores are more susceptible to plugging than are larger pores, and thus if insufficient large pores are present, catalyst activity often declines substantially during use. If catalyst activity declines too rapidly, excessive losses in efficiency and/or increases in catalyst replacement costs are incurred. Thus, sufficient large and small pores must be present.
For example, Kim et al., U.S. Pat. Nos. 4,257,922 and 4,294,685, disclose a catalyst comprising a catalytically active substance on support particles having a bimodal pore distribution, with a peak concentration of small pores having diameters below about 600 .ANG. and a peak concentration of larger pores having diameters above about 600 .ANG., the average diameter of the smaller pores in the range of 100-200 .ANG., and the average diameter of the larger pores being in excess of 1,000 .ANG., and the catalyst having at least 5% of the total pore volume in the larger pores and at least 70% of the total pore volume in the smaller pores. This catalyst is disclosed as being suitable for the hydroconversion of coal solids to liquid and gaseous products.
Hensley et al., U.S. Pat. No. 4,225,421, disclose a similar bimodal catalyst consisting essentially of at least one active hydrogenation metal selected from Group VIB deposited on a support comprising alumina wherein the catalyst has a surface area within the range of from about 140 to about 300 m.sup.2 /gm, a total pore volume based upon measurement by mercury penetration within the range of from about 0.4 cc/gm to about 1.0 cc/gm, and comprising about 60% to about 95% of its micropore volume in micropores having diameters within the range of from about 50 .ANG. to about 200 .ANG., 0% to about 15% of its micropore volume in pores having diameters within the range of about 200 .ANG. to about 600 .ANG. and about 3% to about 30% of the total pore volume based upon measurement by mercury penetration in macropores having diameters of at least 600 .ANG.. The catalyst is disclosed for use in a process for hydrodemetallation and hydrodesulfurization of hydrocarbon feedstocks containing asphaltenes and metals, such as crude oils, topped crude oils, and petroleum hydrocarbon resids, both atmospheric and vacuum resids, oils obtained from tar sands, and resids derived from tar sands oil.
The aforesaid Kim et al. patents disclose a molybdenum component as a suitable catalytically active substance and state that other known catalysts such as nickel and/or cobalt can be employed as promoters for the molybdenum. However, Kim et al. contain no suggestion to promote the catalytic activity of molybdenum with a tin, zinc, lead or vanadium component. Thus far, no one has disclosed a supported Group VIB metal component and a supported tin, zinc, lead or vanadium component and support particles having specific physical properties.
Kiovsky et al., U.S. Pat. No. 3,668,109, disclose a continuous liquid phase tin chloride catalyst for use in the hydroconversion of organic materials, particularly solid or very high boiling organic materials, by contacting such materials with hydrogen at an elevated temperature in the presence of such catalyst. Kiovsky et al., U.S. Pat. Nos. 3,663,452 and 3,725,239, disclose a catalyst comprising a complex salt of a tin or zinc halide and ammonium chloride supported on alumina for use in increasing the rate of hydrogenation of hydrogenatable materials, such as petroleum fractions. However, such disclosures do not indicate an appreciation of the importance of the physical properties of the catalyst with regard to its activity and the maintenance of its activity over an extended period of operation.